The overall goal of this porgram is to expand our knowledge of the mechanisms of cellular responses to hormones and other activators of adenylate cyclases by understanding the regulation and properties of cyclic AMP-dependent protein kinases at three levels of complexity, using: purified enzymes, purified plasma membranes and intact cells. The structural, functional and regulatory properties of a plasma membrane-associated protein kinase in human erythrocytes will be characterized. Physicochemical techniques, photoaffinity labeling, peptide mapping, subunit recombination studies and other functional tests will be used to examine the degree of relatedness between membrane-associated and soluble protein kinases and to determine whether the functional roles of the subunits of membrane-bound kinases are restricted to the membrane environment or play a more versatile role in cell regulation. Purified preparations of erythrocyte membrane protein kinase and bovine brain synaptic membrane protein kinase will be compared as prototypes of two categories of particulate kinases. Other studies will focus on the identification and characterization of a specific membrane anchoring protein responsible for determining the subcellular location and functional roles of the particulate protein kinase. Protein kinase isoenzyme patterns will be correlated with the development of hormone receptors and hormone-sensitive adenylate cyclase during adipocyte differentiation in 3T3-L1 cells. These studied may delineate the degree to which alterations in protein kinase isoenzyme concentrations and localization are coordinated with the development of hormone sensitivity.